<div style="overflow: hidden; background-color: grey; max-width: 50%">
    <div style="width: 20px; height: 20px; background-color: lightblue; float: left"></div>
    <div style="width: 20px; height: 20px; background-color: lightblue; float: right"></div>
    <div style="clear: both"></div>
    <div style="width: 20px; height: 20px; background-color: lightcoral; float: left"></div>
    <div style="width: 20px; height: 20px; background-color: lightcoral; float: right"></div>
</div>
